IO复用poll

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IO复用poll

poll函数

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int poll(struct pollfd fds[],int len,int timeout);

struct pollfd
{
    int fd; 	//用户设置关注的文件描述符
    short events;	//用户关注的事件类型
    short revemts;	//由内核填充，就绪的事件类型
};//成功返回就绪文件描述符的个数，失败返回-1，超时返回0
timeout：定时时间

poll所支持的事件类型

服务端

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#define _GNU_SOURCE

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<assert.h>

#include<sys/types.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>

#include<poll.h>
#define LEN 100
int initsocket()
{
    int sockfd=socket(AF_INET,SOCK_STREAM,0);
    if(sockfd==-1) 
        return -1;

    struct sockaddr_in ser;
    memset(&ser,0,sizeof(ser));
    ser.sin_family=AF_INET;
    ser.sin_port=htons(6000);
    ser.sin_addr.s_addr=inet_addr("127.0.0.1");
    int res=bind(sockfd,(struct sockaddr*)&ser,sizeof(ser));
    if(res==-1)
        return -1;

    res=listen(sockfd,5);
    if(res==-1)
        return -1;
    
    return sockfd;
}
void initfds(struct pollfd *fds)
{
    int i=0;
    for(;i<LEN;++i)
    {
        fds[i].fd=-1;
        fds[i].events=0;
    }
}
void insertfd(struct pollfd *fds,int fd,short events)
{
    int i=0;
    for(;i<LEN;++i)
    {
        if(fds[i].fd==-1)
        {
            fds[i].fd=fd;
            fds[i].events=events;
            break;
        }
    }
}
void dealfinish_event(struct pollfd *fds,int sockfd)
{
    int i=0;
    for(;i<LEN;++i)
    {
        if(fds[i].fd==-1)
            continue;
        else if(fds[i].fd==sockfd)
        {
            if(fds[i].revents&POLLIN)
            {
                struct sockaddr_in cli;
                socklen_t len=sizeof(cli);
                int c=accept(sockfd,(struct sockaddr*)&cli,&len);
                if(c<0)
                {
                    printf("accept error\n");
                    continue;
                }
                printf("one client link success\n");
                insertfd(fds,c,POLLIN|POLLRDHUP);
            }
        }
        else    //客户端连接文件描述符
        {
            if(fds[i].revents&POLLRDHUP)
            {
                printf("one client unlink\n");
                close(fds[i].fd);
                fds[i].fd=-1;
                fds[i].events=0;
            }
            else if(fds[i].revents&POLLIN)
            {
                char buff[128]={0};
                int n=recv(fds[i].fd,buff,127,0);
                if(n<=0)
                {
                    printf("recv error\n");
                    continue;
                }
                printf("%d: %s\n",fds[i].fd,buff);
                send(fds[i].fd,"OK",2,0);
            }
        }
    }
}
int main()
{
    int sockfd=initsocket();
    assert(sockfd!=-1);

    struct pollfd fds[LEN];
    initfds(fds);
    insertfd(fds,sockfd,POLLIN);

    while(1)
    {
        int n=poll(fds,LEN,-1);//n>0返回就绪文件描述符的个数
        if(n<=0)
        {
            printf("poll error\n");
            continue;
        }
        //看下是不是sockfd，是就接受新的客户端连接，不是就是客户端有数据到达
        dealfinish_event(fds,sockfd);
    }
}

客户端

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#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<assert.h>

#include<sys/types.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>

int main()
{
    int sockfd=socket(AF_INET,SOCK_STREAM,0);
    assert(sockfd!=-1);

    struct sockaddr_in ser;
    memset(&ser,0,sizeof(ser));
    ser.sin_family=AF_INET;
    ser.sin_port=htons(6000);
    ser.sin_addr.s_addr=inet_addr("127.0.0.1");

    int res=connect(sockfd,(struct sockaddr*)&ser,sizeof(ser));
    assert(res!=-1);

    while(1)
    {
        printf("please input: ");
        char buff[128]={0};
        fgets(buff,127,stdin);
        if(strncmp(buff,"end",3)==0)
            break;
            
        send(sockfd,buff,strlen(buff)-1,0);

        char result[128]={0};
        int n=recv(sockfd,result,127,0);
        if(n<=0)
            break;
        printf("result: %s\n",result);
    }
    close(sockfd);
}

通信测试